Ch. 18 - Evolution of Populations Flashcards
1
Q
gene pool
A
- all the genes, including all the different alleles for each gene, that are present in a population at any one time
2
Q
allele frequency
A
- the number of times that an allele occurs in a gene pool compared with the number of alleles in that pool for the same gene
3
Q
single - gene trait
A
- trait control by one gene that has two alleles
4
Q
polygenic trait
A
- trait control by two or more genes
5
Q
directional selection
A
- form of natural selection when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve
6
Q
stabilizing selection
A
- form of natural selection in which individuals near the center of a distribution curve have higher fitness than individuals at either end of the curve
7
Q
disruptive selection
A
- natural selection in which individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle of the curve
8
Q
genetic drift
A
- random change in allele frequency caused by a series of chance occurrences that cause an allele to become more or less common in a population
9
Q
bottleneck affect
A
- a change in allele frequency following a dramatic reduction in the size of a population
10
Q
genetic equilibrium
A
- situation in which allele frequencies in a population remain the same
11
Q
Hardy - Weinberg principle
A
- principal that states that allele frequencies in a population remain the same unless one or more factors caused those frequencies to change
12
Q
sexual selection
A
- when individuals select mates based on heritable traits
13
Q
gene flow
A
- the movement of genes into or out of a population
14
Q
speciation
A
- formation of a new species
15
Q
reproductive isolation
A
- separation of a species or population so that they no longer interbreed and evolve into separate species
16
Q
behavioral isolation
A
- form of reproductive isolation in which two populations develop differences in courtship rituals or other behaviors that prevent them from breeding
17
Q
geographical isolation
A
- form of reproductive isolation in which two populations are separated by geographic barriers such as rivers, mountains, or bodies of water, leading to the formation of two separate subspecies
18
Q
temporal isolation
A
- form of reproductive isolation in which two or more species reproduces at different times
19
Q
Hox gene
A
- a group of homeotic genes clustered together that determines the head to tail identity of body parts in animals. All Hox genes contain the homobox DNA sequence
20
Q
Founder effect
A
- a change in allele frequencies as a result of the migration of a small subgroup of a population; new population has less genetic diversity than original population
